Circulating Fluidized Bed Boiler (CFB)
Widely used for low-grade coal and biomass co-firing. Key refractory areas: combustion chamber, cyclone separator, loop seal, and return leg.
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Get PriceWidely used for low-grade coal and biomass co-firing. Key refractory areas: combustion chamber, cyclone separator, loop seal, and return leg.
Dominant technology for large utility boilers. Critical zones: burner zone, furnace walls, slag tap, and nose arch.
Municipal solid waste combustion with severe chlorine and alkali corrosion. Requires high-density SiC and chrome-alumina refractories.
Burning wood chips, straw, and agricultural residues. High risk of alkali-induced slagging and fouling. Specialized alumina-silica materials.
CFB boilers require high abrasion resistance in the dense bed and cyclone. High thermal shock resistance is crucial in start‑up zones.
Main challenges: slagging, thermal shock, and ash corrosion. Burner quarls require high thermal shock resistance.
Severe chlorine, sulfur and alkali attack. High-density low-porosity materials are essential for corrosion resistance.
High alkali content (K, Na) causes severe fouling. Refractories must resist alkali attack and chlorine corrosion.
| Boiler Type / Zone | Operating Conditions | Common Materials | Recommended Materials |
|---|---|---|---|
| CFB – Furnace Water-Wall / Fluidized Bed Area | High temperature, severe abrasion, particle impact | Low Cement High Alumina Castable | Silicon Carbide Castable |
| CFB – Cyclone Separator/td> | High velocity erosion, continuous solid circulation | High Alumina Castable | Abrasion Resistant SiC Castable |
| Pulverized coal – Radiant Zone / Furnace Water-Wall Area | High temperature radiation, thermal cycling, gas erosion | High Alumina Castable | Abrasion Resistant High Alumina Castable |
| Pulverized coal – Burner Throat Area | High flame temperature, high-speed coal particle impact, thermal shock | High Alumina Castable | Silicon Carbide Castable |
| Waste incinerator – Main Combustion Chamber | High temperature, slag attack, chemical corrosion | High Alumina Castable | Silicon Carbide Castable |
| Waste incinerator – Grate & Slag Discharge Area | Mechanical wear, ash erosion, thermal shock | Abrasion Resistant Castable | Silicon Carbide Castable |
| Biomass boiler – Furnace Wall / Combustion Zone | High temperature, ash corrosion, particle erosion | High Alumina Castable | Silicon Carbide Castable |
| Biomass boiler – Grate Area | Mechanical wear, thermal cycling, ash erosion | Abrasion Resistant Castable | SiC Reinforced Castable |
High‑alumina brick with 75–85% Al₂O₃ or andalusite brick is commonly used. For severe wear, SiC castable or nitride‑bonded SiC brick provides outstanding abrasion resistance.
Use low‑porosity mullite or SiC castable with smooth surface. Proper burner design and coal ash chemistry control are also key factors.
Chrome‑alumina brick (Cr₂O₃ content 10–25%) is the standard solution. For less severe areas, high‑density andalusite or SiC brick can also perform well.
Alkali (potassium/sodium) attack leads to chemical corrosion and spalling. Use high‑alumina materials with low alkali content and anti‑alkali additives. Regular coating removal also helps.
No. CFB requires extreme abrasion resistance (SiC, high‑alumina), while pulverized coal boilers focus on slag resistance and thermal shock. Material selection should be zone‑specific.